• Korean Journal of Materials Research
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• v.19 no.4
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• pp.224-227
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• 2009

Nanofabrication is an essential process throughout industry. Technologies that produce general nanofabrication, such as e-beam lithography, dip-pen lithography, DUV lithography, immersion lithography, and laser interference lithography, have drawbacks including complicated processes, low throughput, and high costs, whereas nano-transfer printing (nTP) is inexpensive, simple, and can produce patterns on non-plane substrates and multilayer structures. In general nTP, the coherency of gold-deposited stamps is strengthened by using SAM treatment on substrates, so the gold patterns are transferred from stamps to substrates. However, it is hard to apply to transfer other metallic materials, and the existing nTP process requires a complicated surface treatment. Therefore, it is necessary to simplify the nTP technology to obtain an easy and simple method for fabricating metal patterns. In this paper, asnTP process with poly vinyl alcohol (PVA) mold was proposed without any chemical treatment. At first, a PVA mold was duplicated from the master mold. Then, a Mo layer, with a thickness of 20 nm, was deposited on the PVA mold. The Mo deposited PVA mold was put on the Si wafer substrate, and nTP process progressed. After the nTP process, the PVA mold was removed using DI water, and transferred Mo nano patterns were characterized by a Scanning electron micrograph (SEM) and Energy Dispersive spectroscopy (EDS).

• Journal of the Korean Solar Energy Society
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• v.29 no.1
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• pp.32-37
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• 2009

Photovoltaic(PV) permits the on-site production of electricity without concern for fuel supply or environmental adverse effects. The electrical power is produced without noise and little depletion of resources. So BIPV(Building-Integrated Photovoltaic) system have been increased around the world. Hereby the relative installation costs of the system will be relatively low compared to traditional installations of PV in high-rise buildings. This paper examined possibility of building integrated balcony PV system and analyzed both performance and problems of this system. The system is influenced by conditions such as irradiation, module temperature, shade and architectural component etc. If this BIPV system of 1.1kW is possible the natural ventilation in the summer case, the temperature of PV module decrease and then the efficiency of PV system increase generally. By the results, the annual averaged PR of BIPV system of cold facade type is about 74.7%.

• Convergence Security Journal
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• v.15 no.5
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• pp.3-8
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• 2015

Most mobile cloud computing system use public key cryptography to provide data security and mutual authentication. A variant of traditional public key technologies called Identity-Based Cryptography(IBC) has recently received considerable attention. The certificate-free approach of IBC may well match the dynamic qualities of cloud environment. But, there is a need for a lightweight secure framework that provides security with minimum processing overhead on mobile devices. In this paper, we propose to use hierarchical ID-Based Encryption in mobile cloud computing. It is suitable for a mobile network since it can reduce the workload of root Public Key Generators by delegating the privilege of user authentication and private key generation. The Identity-Based Encryption and Identity-Based Signature are also proposed and an ID-Based Authentication scheme is presented to secure data processing. The proposed scheme is designed by one-way hash functions and XOR operations, thus has low computation costs for mobile users.

• The Journal of Korean society of community based occupational therapy
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• v.5 no.1
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• pp.35-43
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• 2015

Objective : The purpose of the study is to find the factors affecting a social phenomena of the elderly and suggest a basic data for efficiency of a senior policy and type of the life in Korea. Methods : We refereed to sources from the Korean Statistical Information, the National Pension Service, and the Ministry of Health and Welfare. We also surveyed and analysed the depression and death anxiety among the elderly in 2014. Results : First, most of them were low educated people and family composing a couple. An annual income were average. Second, medical costs were increasing constantly in proportion to the increase of aging population. Third, they had high depression index resulting from negative thinking of the future and themselves. Fourth, the death anxiety level of them were more than moderate and that was about the death of themselves and the process of the death. Conclusion : It is needed to help physical, mental, and social health and improve the quality of the life in the elderly through social program established a variety of special fields like occupational therapy and family support program belonging to the government.

• KIEAE Journal
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• v.13 no.3
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• pp.71-78
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• 2013

A need for building energy efficiency is on the issue since energy demand in the building stock in Korea represents about 24% of the final energy consumption. As a way of improving the thermal performance of buildings for reducing maintenance costs and environmental conservation, a lot of effort is shown to improve the building energy efficiency by applying improvement of envelope insulation performance for buildings whose energy efficiency is low relatively through the remodeling. The windows of building envelopes are areas that lead to the biggest heat loss in the building. So windows are considered to be the primary target of energy efficiency in remodeling and various studies for windows have been done. Currently, however, only U-factor and airtightness of windows performance are regulated. Window wall ratio(WWR) and solar heat gain coefficient(SHGC) of windows are not considered when conducting the remodeling. In this study appropriate performance of windows(U-factor and SHGC) for existing residential is proposed according to the window wall ratio by using EnergyPlus. As the results of this study, the U-factor of windows representing the maximum energy savings is $1.0W/m^2K$ but in case of SHGC, the values that indicate the maximum energy savings are different depending on the window wall ratio. Therefore, when conducting the remodeling of windows, to determine energy efficiency by considering only the U-factor is inadequate so it is necessary that appropriate windows are applied to buildings by considering window wall ratio and windows properties(U-factor and SHGC).

• Journal of Ocean Engineering and Technology
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• v.28 no.3
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• pp.218-226
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• 2014

Since the support structure of an offshore wind turbine has to withstand severe environmental loads such as wind, wave, and seismic loads during its entire service life, the need for a robust and reliable design increases, along with the need for a cost effective design. In addition, a robust and reliable support structure contributes to the high availability of a wind turbine and low maintenance costs. From this point of view, this paper presents a design process that includes design optimization and reliability analysis. First, the jacket structure of the NREL 5-MW offshore wind turbine is optimized to minimize the weight and stresses, while satisfying the design requirements. Second, the reliability of the optimum design is evaluated and compared with that of the initial design. Although the present study results in a new optimum shape for a jacket support structure with reduced weight and increased reliability, the authors suggest that the optimum design has to be accompanied by a reliability analysis during the design process, as well as reliability based design optimization if needed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.11B
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• pp.655-662
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• 2007

Monitoring systems used at present to operate HVAC(Heating, Ventilation and Air Conditioning) optimally do not have a function that enables to detect faults properly when there are faults of such as operating plants or performance falling, so they are unable to manage faults rapidly and operate optimally. In this paper, we have developed a classified rule-based fault detection system which can be inclusively used in HVAC system of a building by installation of sensor which is composed of HVAC system and required low costs compare to the model based fault detection system which can be used only in a special building or system. In order to experiment this algorithm, it was applied to HVAC system which is installed inside EC(Environment Chamber), verified its own practical effect, and confirmed its own applicability to the related field in the future.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.5
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• pp.667-679
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• 2015

The bearer of the power sector's ETS compliance cost is power consumer for the following reasons. Firstly, power companies are constrained in establishing appropriate strategies to comply with ETS regulations due to the structural differences between the domestic power market and emission trading system. In other words, because power companies do not have a right to determine price and production of electricity, they have to compete with other companies under disadvantaged conditions in the emission trading market. Secondly, because ETS compliance cost is part of power production costs as it is also clearly written in the national greenhouse gas reduction road-map and the second energy supply plan, the cost should be included in power price following the power market operation rule. Thirdly, the most effective method to reduce carbon emissions in power sector is to reduce power demand, which is efficiently achieved through raising power price to a realistic level. Low power price in Korea is the major cause of rising power demand which is also the major cause of rising GHG emission. Therefore, power sector's ETS compliance cost should be included in power price to encourage power consumers' actions on reducing power consumption. Fourthly, when externality cost occurs in the process of delivering public services, usually beneficiary pay principle is applied to identify the cost bearer. Since electricity is one representative public good, the bearer of power sector's ETS compliance cost is power consumer.

• Environmental and Resource Economics Review
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• v.11 no.2
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• pp.211-231
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• 2002

This paper summarizes the results of a study that assess how a demand side management (DSM) system addresses key economic and environmental challenges facing in the Korean natural gas sector considering; ${\bullet}$ high discrepancies of seasonal consumption volume and of load factor in unmatured domestic LNG market, ${\bullet}$ unfavorable and volatile international LNG market, imposing with the contestable "take-or-pay" contract terms, ${\bullet}$ low profile of LNG and existence of market barriers against an optimal fuel mix status in the industrial energy sector. A particular focus of this study is to establish an 'extended' DSM system in the unmatured gas market, especially in industry sector, that could play a key role to assure an optimum fuel mix scheme. Under the concept of 'extended' DSM, a system dynamics modeling approach has been introduced to explore the option to maximize economic benefits in terms of the national energy system optimization, entailing different ways of commitments accounting for different DSM measures and time delay scenarios. The study concludes that policy options exist that can reduce inefficiencies in gas industry and end-use system at no net costs to national economy. The most scenarios find that, by the year 2015, it is possible to develop a substantial potential of increased industrial gas end-uses under more reliable and stable load patterns. Assessment of sensitivity analysis suggests that time delay factor, in formulating DSM scenarios, plays a key role to overcome various market barriers in domestic LNG market and provides a strong justification for the policy portfolios 'just in time' (time accurateness), which eventually contribute to establish an optimum fuel mix strategy. The study indicates also the needs of advanced studies based on SD approach to articulate uncertainty in unmatured energy market analysis, including gas.

• Korean Journal of Community Nutrition
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• v.23 no.3
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• pp.226-233
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• 2018

Objectives: This study was conducted to investigate the current status and to suggest future directions for health management of teenagers who use healthy school tuck shops to improve teenagers' eating habits while reducing and preventing obesity. Methods: A total of 29 students (16 middle school students and 13 high school students) took part in the interview for this study, and the interview was conducted for each school's focus group by using qualitative research methodology. Results: The current status of using healthy school tuck shops and suggested future directions were divided into two categories. Personal barriers such as discrepancies between personal perceptions and behaviors and lack of food choice suitable to individual tastes can be solved by rebuilding the operating system to provide intuitive promotion of behavior and customized products through improvements in existing products and new product development. A lack of consistent management from low utilization convenience and difficulty in maintaining a constant purchase price can be handled by establishing a solution to restricted physical access for products, as well as seeking profit by improving distribution costs via continuous cooperation between the school and community. Conclusions: Continuous funding and a system that reflects the needs and preferences of healthy school tuck shop users should be applied for sustainable operation of healthy school tuck shops to improve teenagers' eating habits.